1. Field of the Invention
The present invention relates to an air conditioner control system installed on an automobile and, more particularly, to an air conditioner control system which is enabled to set a desired temperature by changing the open angle of an air mixing door.
2. Description of the Prior Art
Before entering into the detailed description of the present invention, cursory review of the prior art will be made in the following with reference to the accompanying drawings.
FIG. 4 is a schematic diagram for explaining an ordinary air conditioner which is installed on an automobile.
As shown in FIG. 4, the air conditioner is equipped therein with a variety of doors having different functions. At first, the internal and external air change is undergone by means of an intake door 12 for selectively sucking the air from the inside or outside of the car compartment into the air conditioner. The air having passed through that intake door 12 is fed by the action of a fan motor 13 to an evaporator 14. This evaporator 14 functions to forcibly cool and send out the air fed. Then, the air having passed through the evaporator 14 is separated into one to be used as a cool wind without any treatment and the other to be heated by a heater core 15 so that it may be used as a warm wind until the cool air and the warm air are later mixed to prepare a wind at a suitable temperature. In order to determine the mixing ratio of those cool and warm winds, moreover, there is provided an air mixing door 11. In dependence upon the opening degree of this air mixing door 11, the desirably air-conditioned wind can accordingly be prepared. The wind thus prepared is then fed to a ventilation door 17, a floor door 18 and a defrost door 19 so that the respective air exits are selected in dependence upon the opening states of those doors 17, 18 and 19 to feed the properly air-conditioned wind from the exit selected.
As has been described above, the automotive air conditioner is equipped with the various doors, of which the intake door 12, the ventilation door 17, the floor door 18 and the defrost door 19 may be selectively opened or closed whereas exclusively the air mixing door 11 has to be continuously opened and closed because it is required to have a variety of opening states.
FIG. 5 is a perspective view showing an example of the drive mechanism for driving the air mixing door according to the prior art. In FIG. 5, reference numeral 20 denotes an L-shaped lever, and numeral 21 denotes a wire.
As shown in the same Figure, the lever 20 is hinged at a pin 20b so that it can swing in the directions of arrows A--A, whereas the air mixing door 11 is hinged at pins 11a so that it can swing in the directions of arrows B--B. The wire 21 is connected between one end 20c of the lever 20 and the air mixing door 11. If a control knob 20a fitted on the other end of the lever 20 is manually moved in the directions of the arrows A--A, these motions can accordingly be transmitted through the wire 21 to the air mixing door 11 to rotate this door 11 at a desired angle in the directions of the arrows B--B in accordance with the motions of the lever 20.
In the drive mechanism of this manual type, however, the air mixing door 11 is driven by the actuation of the lever 20 so that the manual force required is high. Especially during the ventilation, the air mixing door 11 is subjected to the wind pressure so that the lever 20 has to be actuated by a higher manual force to raise a defect that the lever 20 becomes difficult to actuate.
In order to eliminate this defect concomitant with the manual type drive mechanism, therefore, we have proposed an electric drive mechanism for opening and closing the air mixing door by the driving force of a motor.
FIGS. 6, 7 and 8 are a perspective view and diagrams showing the air conditioner control system proposed previously and for explaining the changing operations of a toggle switch attached to said system.
In FIG. 6, reference numeral 1 denotes a control knob which is adapted to be linearly moved thereby to change the temperature. And, this control knob 1 is fixedly fitted on a projection 3a of a toggle switch 3 through a front panel 2 which is graduated in temperatures or the like. As a result, the control knob 1 and the toggle switch 3 are associated with each other.
Denoted at numeral 4 is a case which cases the aforementioned toggle switch 3 and a later-described cam follower 5. This case 4 is formed with guide grooves 4a and 4b for linearly moving those toggle switch 3 and cam follower 5.
At the end opposed to the projection 3a, on the other hand, the toggle switch 3 carries a change lever 3b. The cam follower 5 is formed with a generally V-shaped notch 5a which can engage with and disengage from that change lever 3b. With the toggle switch 3, moreover, there is connected through cords 6 a motor 7 which is so wired that it is interrupted and turned forward and backward by the changing operations of the change lever 3b.
These wiring connections will be described in detail with reference to FIGS. 7(a), 7(b) and 7(c). In case the aforementioned toggle switch 3 faces the cam follower 5 to have its change lever 3b engaging with the notch 5a, it is in its OFF position, in which no power is supplied to interrupt the motor 7, as seen from the circuit diagram of FIG. 7(a).
In case the toggle switch 3 is moved from this state rightwardly of the drawing so that the change lever 3b is brought down leftwardly of the drawing by the notch 5a, as shown in FIG. 7(b), the motor 7 is energized to turn forward (i.e., clockwise of the drawing).
In case, on the contrary, the toggle switch 3 is moved leftwardly of the drawing so that the change lever 3b is brought down rightwardly of the drawing by the notch 5a, as shown in FIG. 7(c), the current flows in the reverse direction to that of the case of FIG. 7(b) so that the motor 7 is energized to turn backward (i.e., counter-clockwise of the drawing).
Reverting to FIG. 6, there is fixed to the shaft 7a of the motor 7 a planar actuator 8 to which are connected one end of a feedback wire 9 and one end of a wire 10. The other end of the feedback wire 9 is connected to the aforementioned cam follower 5 whereas the other end of the wire 10 is connected to a substantially central portion of one end face of the air mixing door 11. In the two end faces of the lower portion of that air mixing door 11, moreover, there are anchored the pins 11a which provide the fulcrum when the door 11 is to be opened and closed.
Next, the operations of the air conditioner control system thus constructed will be described mainly with reference to FIG. 8.
FIG. 8(a) shows the stopped state of the air mixing door 11. Since, in this state, the change lever 3b of the toggle switch 3 and the notch 5a of the cam follower 5 are in engagement with each other, the toggle switch 3 is in its OFF state so that the motor 7 is interrupted to leave the air mixing door 11 in the upright position.
If the control knob 1 is manually actuated from this state to move the toggle switch 3 rightwardly of the drawing, the change lever 3b is brought down leftward, as shown in FIG. 8(b), so that the motor 7 undergoes the rotational drive in the clockwise direction. As a result, the actuator 8 fixed on the shaft 7a is turned clockwise to pull the cam follower 5 connected to said actuator 8 through the feedback wire 9, rightwardly of the drawing. When the cam follower 5 is moved to face the toggle switch 3, the change lever 3b restores its engagement with the notch 5a so that the motor 7 also restores its interrupted state. In this meanwhile, the air mixing door 11 is pushed rightward in association with the movement of the aforementioned cam follower 5 because it is connected through the wire 10 to the aforementioned actuator 8. As a result, the air mixing door 11 is brought down rightward on its pins 11a, as shown in FIG. 8(c).
If the control knob 1 is then actuated from this state leftward to move the toggle switch 3 leftward from the state of FIG. 8(a), the change lever 3b is brought down rightward, as shown in FIG. 8(d), so that the motor 7 undergoes its rotational drive in the counter-clockwise direction. As a result, the actuator 8 is turned counter-clockwise so that the cam follower 5 is pushed leftwardly of the drawing through the feedback wire 9 until it comes to face the toggle switch 3. When the change lever 3b comes into engagement with the notch 5a, the motor 7 comes into its interrupted state. Since the air mixing door 11 is also pulled at this time leftwardly of the drawing by the wire 10 in association with the movement of the cam follower 5, it is brought down to the left on its pins 11a, as shown in FIG. 8(e).
With the construction thus far described, when the change switch is slid a predetermined stroke by the control knob to energize the motor, this motor can be interrupted by causing the cam follower to follow the change switch a stroke according to the sliding stroke. As a result, the opening angle of the air mixing door can be controlled not manually but electrically in a fine manner in accordance with the movement of the control knob to set the temperature accurately.
However, the air conditioner control systems of the prior art are troubled by the facts that they are complicated to require a wide space for accommodation and that they are limited in their installations.